Internal combustion engine



Aug. 23, 1938. M. KADENACY INTERNAL COMBUSTION ENGINE Filed Sept. 27, 1954 5 Sheets-Sheet l Aug. 23, 1938. M. KADENACY INTERNAL COMBQSTION ENGINE Filed Sept. 27, 1934 5 Sheqts-$heet 3 Aug. 23, 1938. I M. KADENACY $127,775

INTERNAL COMBUSTION ENGINE Filed Sept. 27, 1954 5 Sheets-$heet 4 AIR/1 Aug. 23, 1938. M. KADENACY INTERNAL COMBUSTION ENGINE Filed Sept. 27. 1954 5 Shets-Sheet 5 Patented Aug. 23, 1938 V UNITED STATE alarms m'rsamr. cormus'rrox enema Michel Kadenm, Paris, France Application v In -. 14 Claims.

This invention relates to two stroke cycle internal. combustion engines operatingonpetrol or heavy oil or any other combustible fuel, in which the vacuum or high depression left in the working chamber by the exit of the explosion gases from the latter, substantially as a mass is utilized for introducing a new charge under atmospheric pressure.

In such engines it is found that at certain speeds a torque or brake means effective pressure is obtained or approached which is practically ideal for the engine under consideration and that at other speeds the torque falls below this optimum value for reasons inherent to the particular construction adopted, but always because at these moments the quantity of pure air retained in the working chamber is insufllcient to give the optimum torque.

The main object of the invention is to provide an improvement in such an engine which permits these falls in the value of the torque to be corrected or compensated at different speeds and combats the progressive reduction in the amount of air drawn in naturally under atmospheric pressure during the main charging, thereby rendering the engine torque stable at all speed ranges within practical limits.

A further object is to enable the engine to be unafiected by any objectionable influences arising from the provision of silencers and from piping which may extend from the latter.

The invention will now be described with reference to the accompanying drawings, in which- Figure l is a general diagram illustrating the basis of the improvements according to the present invention.

Figure 2 shows curves illustrating the application of the invention to engines of the type in question.

Figure 3 illustrates generally the application of the invention to engines in which the main. exhaust port closes after the main admission port.

Figure 4 is a timing diagram relating to Figure 3.

Figure 5 illustrates the general application of the invention to engines in which the main exhaust port closes before the main admission port.

Figure 6 is a timing diagram relating to Figure 5, and

Figure 7 indicates an engine. I

Figure 8 represents a particular case of an engine cylinder such as that shown in Figure 3 curves obtained with such pression, the volume September 27, 1984. Serial No. "5,814 Great Britain August 14, 1934 (or. 123-85l v and serves to illustrate another feature of the invention.

Figure 9 is a timing diagram relating to Figure 8.

Figure 10 shows curves relating to the arraniements described with reference to Figures 8 and 9. Figure 11 relates to a detail of the invention.

In an -engine of the type to which the invention relates, exhaust is eifected by employing the energy of the explosion gases and the vacuum or the high depression left in the working chamber by theexplosion gases when they are discharged from the latter substantially as a mass for recharging.

These conditions of operation are illustrated in Figure 1 in" which E0 is the point at which exhaust opens, and the angle 1! indicates the part of the cycle occupied by the massexit of the burnt gases.

The admission Acommences at A0, about or a little before the end of-the mass exit and while the exhaust port is still open, and it closes at a point established in a normal manner.

On account of the high depression existing in the cylinder at the end of the mass exit of the burnt gases and of the small quantity of residual cases contained therein, there will never be any advantage in commencing the main admission under compression g The main charge is admitted under atmospheric pressure, as stated above. and this charge is suckedinto the cylinder from the atmosphere by the depression, without any preliminary comof air thus admitted being approximateLv equal to or even greater than the cylinder volume. Y

The charge thus admitted will reach a pressure approaching atmospheric pressure more or less according to the moment in which the exhaust port closes positively and according to the shape of the cylinder and the characteristics of the distribution and of the exhaust.

Various means have already been put forward by the applicant for constructing an engine operating in the manner described above.

All these constructions employed alone give optimum points in the operation of the engine on either side of which the mean effective pressure falls away more or less rapidly.

In particular the applicant in a British specification No. 35,067} 33 has described the influence of the exhaust pipe upon the peak point; and in another British specification No. 35,068/33, he has described the influence of the angular separation between exhaust opening and inlet opening.

With an engine constructed according to one or the other of these two British specifications, a curve maybe obtained such as the curve I in Figure 2, in which the ordinates represent B. H. P., the abscissae represent R. P. M., and the polar straight lines represent ideal B. H. P./R. P. M. curves at different brake mean effective pressures.

The reasons for which these curves adopt this form are as follows:

The violence of the explosion is proportional to the quantity of fresh air (oxygen), to the quantityof. fuel introduced, to the more or less exact proportions of these two elements and then to the pressure and the temperature at the moment of the explosion.

The quantity of air which enters the cylinder is proportional to the intensity of the depression and volume of the space in which this depression exists. This volume and this intensity are dependent upon the violence of the explosion per unit of the explosive masses.

In the case as described above, if the speed 01' the engine is changed, the moment at which the admission of the gases commences becomes situated a little before or a little after the most favourable moment for utilizing theiwhole of the volume and the whole of the intensity of the depression in the space to be filled.

As a consequence the amount of fresh air admitted is reduced to unfavourable proportions. If the quantity of fuel introduced remains the same, a less violent explosion will follow for the two following reasons which combine in their action-(1) the reduction of oxygen and 2) the bad proportion between-air and fuel.

As a consequence the output of the engine commences to fall until it becomes stabilized at a lower level.

If there is a depression in the exhaust piping which lasts too long after the closure of the admission, and if the exhaust is then still open, a suction will be produced upon the charge in the cylinder, and in this case the quantity stored in the cylinder at the moment of closure of the exhaust port or of the last port to close will be under a partial vacuum and the final compression at the moment of explosion will be reduced, consequently the charge drawn in will again commence to decrease and a still weaker explosion will follow.

This affords another explanation of curve I in Figure 2.

By combining the means provided according to the above two British specifications, and by suitably situating their peak points at two adjacent speeds, the peak portion of the B. M. E. P. of the engine is flattened out and extended, and a curve such as the curve 2 is obtained.

Further, in another British specification No. 35,069/33, the applicant has described means which permit the cylinder to be protected more effectively from'the effect of the return of the burnt gases to the cylinder and to stabilize this unstable phenomena with variations in the speed of the engine. i

If these means are employed in combination with the foregoing, the range of speeds over which the engine maintains its peak B. M. E. P., is still further extended and a curve such as the curve 3 in Figure 2 is obtained.

According to the case, the degree of stability thus obtained may extend over a varying range of speeds and mayeven extend in a favourable case over 50% of the running speeds of the engine.

The above remarks which are the result of practical experience, show very clearly that the curve of engines of the type to which the invention relates present anomalies which are of an increasing or decreasing order and become stabilized at certain values and at certain engine speeds.

It also appears that even the peak points which are indicated on the curves by the letter are points of stability, which may themselves be lower than the value which the air introduced into the cylinder by the vacuum left by the issuing gases can produce in the output of the engine.

In view of the fact that after each fresh explosion, the out of balance effect increases always until a new point of stability is reached, it is clear that by introducing into the cylinder :1 small quantity of supplementary air a little greater than the resultant loss after each explosion, the engine will be stabilized at its optimum output for the quantity of fuel introduced.

As a consequence the amount of air to be added to the natural atmospheric charge contained in the cylinder is very small. It may vary between 5% and 25% of the cylinder volume and in certain cases it is even less than 5%. For example an opposed'piston engine constructed by the applicant gave a B. M. E. P. of 142 lbs/sq. in., at about 1200 R. P. M.

The quantity of air drawn by suction into the cylinder measured 860 c. c., the volume of the cylinder being 700 c. c.

At a speed of 900 R. P. M. with disturbances producing a reduction in the amount of fresh air retained in the cylinder, the mean pressure fell to 99.4 lbs/sq. in., and the quantity of air supplied measured 700 c. c. This reduction in the pressure and in the quartity of air sucked in occurred in successive steps and represented a new point of stabilization for the engine.

, A correction was required but this correction was not 160 c. c. as it might appear. On the contrary, it was found that by introducing a supplementary charge of 50 c. c., the B. M. E. P. rose and became stabilized at 142 lbs/sq. in., for all speeds.

It will thus be seen from the foregoing that the engine can be stabilized very advantageously by means of supplementary air preferably introduced under pressure, so as to ensure or supply a quantity of air sufficient to absorb the highest charges of fuel compatible with the cylinder volume.

It is clear that if it is desired to supercharge the engine according to the invention, the normal charge must first be utilized and must then be completed by the supercharge proper.

In this case the supercharge will blend with the supplementary charge, which will be supplied at or towards the end of the admission and will be prolonged a little further after the closure of the last port in order to give the superchargef or the pressure of the supplementary air will be increased; or the supplementary air will be admitted under a high pressure.

As a general rule the supplementary air should be introduced towards the end of the natural atmospheric admission and prolonged a little after the closure 01' the last port.

This supplement will always be less than the volume of the working chamber and will be introduced under a pressure higher than atmospheric pressure.

not be to the best advantage to utilize the whole of this period for this purpose, because some of the advantage of recharging by utilization of the depression existing in the cylinder would thereby be lost.

In order to correct or compensate this main admission obtained by utilization of the depression, the supplementary admission should be ef-. fected towards the end of the main admission, after full use has been made of the depression !or recharging.

The useful angle of the cycle is-indicated diagrammatically by the. angle C in Figure 1; This angle commences towards the end of the atmospheric admission and terminates a little after the closure of the last exhaust or admission port.

Two main cases may be considered:

(a) In which the exhaust closes aiter inlet.

(1)) In which exhaust closes before inlet.

As an example of the first case, we may comsider the engine cylinder illustrated in Figure 3, in which the main exhaust port E and inlet port A are both controlled by the single piston.

The timing diagram oi. such an engineis illustrated in Figure 4, in which the exhaust opens a at E; inlet opens a little after at A0 and closes at AC, and exhaust closes at EC, a little after AC.

In this case the cylinder, while being charged .under atmospheric pressure, remains under a partial vacuum on account of the suction through the exhaust.

The 3:11. P./R. P. M. curve with full unusation of the admission by suction will be such as the curve 3 (Figure 2). This curve will have a peak stabilization point 01 about 85.2 lbs/sq. in.

B. M. E. P., which pressure is nevertheless well below the ideal point. The practical ideal stabilization point will be around 142 lbs./sq. in.

A supplementary charge in this case not only renders the engine stable at all speeds, but liits the highest polntto 142 lbs./sq. in., so that the B. H. PJR. P. M. curve becomes the curve 4 (Figure 1).

This supplementary charge may conveniently be introduced through the supplementary inlet -D connected to a compressor such as that indicated diagrammatically at P'and controlled by a valve such as C, operated by suitable means such as the push rod V and rocker arm R.

In Figure i it is seen that the supplementary compressed, charge will extend over the angle C, commencing at G0 a little before the closure of the main admission port, and terminating at CC a little after the closure of exhaust.

The quantity or air indispensable in this case is small.

For example an engine of 1.5 litres turning at 1300 R. P. M. constructed by the applicant gives a B. M. E. P. of 85.2 lbs/sq. in., and an output of 24 B. H. P. with the main charge admitted With the supplementary air supplied at a more or less high pressure in the manner described alcove through suitable distribution oriiices the H. M. E. P. be comes 142 lbs/sq. in., and the B. iii. l9. ill.

I! it is desired to apply; a supercharge. this I supercharge may be made by continuing the sup plementary charge a little further alter the oldsure of the exhaust port. 1

Figure 5 illustrates an engine cylinder with opposedpistons, as an example of case (b) when inlet closes after exhaust.

In .this example the main inlet ports A and exhaust port E are at the opposite ends of the cylinder..

A supplementary inlet port F is provided at the same end of the cylinder as the admission ports A. This port F is controlled by a slide G and is in connection with .a source of compressed air such as the compressor H.

The timing diagram is illustrated in Figure 6. In this case the supplementary admission will commence at CD. a little before the closure of the exhaust port and will terminate at CC. a little after closure of the main inlet port.

The B. H. PJR. P. M. curves obtained are indicateddn Figure 7. The line 3-3 represents the practically ideal curve at a B. M. E. P. or 142 lbs/sq. in., for the engine, and the curve l-2 is the curve given by the main atmospheric charging.

It will be seen that the peak point or this curve is situated on the ideal line 8-3, and that it is, therefore, necessary tocorrect the other parts of thecurve 1-2 where the values fall below 3-3.

The eiIect of the supplementary air is to bring the curve into the position 3-4. As can be seen from this curve 3-4, the supplementary air has corrected the curve l--2 both at low and high speeds. l V

In bothcases a and b, when it is desired to obtain a supercharge the compressor which gives the supplementary charge will "be employed tor the supercharge, and this supplementary ad- In view of the fact that the supplementary charge (and the supercharge, when there is any) admitted is not great in proportion to the volume of the cylinder and that t e crank angle occupied by this admission is latlvely short, it will always be advantageous to admit this supplementary charge under a fairly high pressure and through relatively small distribution oriiices, whereby a mechanical simplification and economy are obtained.

A high pressure for the supplementary air or the supercharge, presents no objections, because since the volume 01' air admitted is small, the expenditure in horse power is small in proportion to the increase in output obtained from the engine.

In an engine of the type to which the invention relates, no scavenging is necessary for the workings! the engine.

Consequently, the timing of the engine may be so established that the exhaust port is close soon alter the main inlet port opens.

It will, however,- be advantageous'to continue the exhaust opening a little further and to close it aite'r it has been employed usefully, for example at the moment when the charging air reaches the exhaust port and is about to escape through the latter. I

An example of such an arrangement is given in Figure 9, which represents a timing diagram for a two-stroke engine, in which exhaust is closed at or about the end of the period of useful employment of the depression left in the cylinder by the issuing explosiongases.

In this example exhaust opens in the usual manner at E0 and inlet opens a little later at a consequence of the mass exit of the burnt gases therefrom.

Exhaust and inlet then remain open together for a period of time during which charge is effected by atmospheric pressure.

A little after bottom dead centre, exhaust is closed at EC and the admission continues for recharging the cylinder up to a point AC established in a normal manner.

Figure 8 illustrates diagrammatically an engine cylinder adapted to operate according to this cycle and having the main inlet and exhaust orifices at the opposite ends of the cylinder.

. The main atmospheric admission valve is indicated at A and the exhaust port at E". The supplementary inlet port is indicated at J, and is in connection with a source of compressed air such as the compressor K. With the main charging effected under atmospheric pressure, this engine gives a curve such as the curve l-2 in Figure 10, having a peak point at 85.2 lbs/sq. in.

In such an engine it may be of advantage to open a supplementary outlet B to the atmosphereat or about the closure of the main exhaust port E" and before the closure of the admission port A".

By this means the inertia of the entering air is employed in order to the cylinder. This improves the cooling, gives greater purity to the charge and increases the amount of air admitted under atmospheric pressure by the main charging.

The portion of the cycle through which such a communication may be opened is shown in Figure 9 at 30-38. It will be seen that in this example the said communication opens a little before the closure of the main exhaust port (EC), and closes a little before the closure of the main admission ports (AC). This result may be obtained by arranging the supplementary outlet B to the atmosphere at the end of the cylinder opposite the main admission port and by controlling this outlet by any suitable means such 'iected.

a little after. the opening of themain'inlet port,

as a sleeve L. In the latter case any suitable means which are indicated at C will be provided in order to close the main exhaust port while the outlet B opens. By the use of this supplementary outlet the curve of the engine is brought into the position 3-4 (Figure 10).

It is seen that the peak point does not change but that at slow speeds the curve is brought nearer the ideal curve at 85.2 lbs/sq. in. If now the supplementary charge is applied, this will commenceat CO, a little before the closure of the additional outlet and will terminate at CC, a little after.the closure of the main admission.

The curve is thus raised to the position 5-6 and now coincides with the ideal curve at 142 lbs/sq. in. and is stable at slow and high speeds.

When the exhaust and inlet orifices are-at the same end of the cylinder it'will be advan tageous to provide means for dislodging the' pocket of burnt gases which may be retained in the other end of the cylinder. This object may be attained by providing a valve at this end of the cylinder and controlling this valve in such a manner as to admit a small quantity of additional air sufiicient to dislodge the pocket of burnt gases fromthis end of the cylinder.

Figure 11 shows the portion of the cycle during which this additional admission should be ef- It may commence at D0 or about or and it may terminate at DC shortly after.

Such a valve may also serve for admitting the pass more air throughsupplementary charge and/or the supercharge by means of a suitable control. In this case the valve will open twice.

In the examples described above, an indication has been given of the appropriate and advantageous time for eifecting a supercharge. The advantages that can be obtained with supercharging in an engine of the type described will be better appreciated by considering that in all known supercharged engines, the supercharge becomes confused with the main charge.

According to the present invention, the main charge enters naturally under atmospheric pres sure. The source of compression will only have to supply the quantity of air required in order to bring the pressure in the cylinder to normal atmospheric pressure as in the case of high altitudes, or to increase the pressure in the cylinder above atmospheric pressure in the case of supercharged engines.

There will, therefore, be a great advantage in the economy of power required in order to pro-- duce this effect, as compared with known supercharged engines.

I claim:

1. A method of charging two-stroke cycle internal combustion engines, which comprises introducing the main charge by atmospheric pressure, by controlling an inlet orifice so that the said inlet orifice is opened when the exhaust gases are moving outwardly through the exhaust passage consequent upon their mass exit from the cylinder and while the exhaust orifice remains open and in introducing supplementary charge under a pressure higher than atmospheric pressure towards the end of the atmospheric admission period, the said supplementary introduction of charge being continued until shortly after the closure of the main inlet and exhaust orifices in order to ensure atmospheric pressure in the closed cylinder.

2. A method of charging two-stroke cycle internal combustion-engines, which comprises introducing the main charge by atmospheric pressure, by controlling an inlet orifice so that the said inlet orifice is opened when the exhaust gases are moving outwardly through the exhaustpassage consequent upon their mass exit from" the cylinder and while the exhaust orifice remains open and in introducing supplementary charge under a pressure higher than atmospheric pressure towards the end of the atmospheric admission period. the said supplementary introduction of charge being continued after the closure of the main inlet and exhaust orifice in order to supply a supercharge.

3. A method of charging two-stroke cycle internal combustion engines which comprises introducing the main charge by atmospheric pressure, by controlling an inlet orifice so that the said inlet orifice is opened when the exhaust gases are moving outwardly through sage consequent upon their mass exit from the cylinder and while the exhaust orifice remains open, and so that the said inlet orifice is reclosed after the said exhaust orifice is closed, and in introducing supplementary charge under a presthe exhaust passure higher than atmospheric pressure towards the end of the atmospheric charging period, the said supplementary introduction of charge commencing shortly before the end of the atmospheric admission period and terminating shortly .after' the end or the atmospheric admission period. 4. A method or charging two-stroke cycle internal combustion engines, which comprises introducing the main charge by atmospheric pressure, by controlling an inlet orifice so that the said inlet orifice is opened when the exhaust full progress and causes the burnt gases from the cylinder into an exhaust system substantially as a mass, admitting fresh charge into the cylinder by atmospheric pressure when the said issuance of the burnt gases is in a suction effect to be exerted in the cylinder, while the exhaust port is stillopen, in the interval elapsing between the said exit of the burnt gases and the instant when the pressure of the returning gases becomes effective within the cylinder, and introducing supplementar-y charge into the cylinder under a pressure higher than atmospheric pressure in the interval between the commencement of the atmospheric charging period and the instant of closure of the last port to close.

6. A method of charging two-stroke cycle internal combustion engines which comprises introducing the main charge by atmospheric pressure, by controlling an inlet orifice so that the said inlet orifice is opened when the exhaust gases are moving outwardly through the exhaust passage as a consequence of their, mass exit from the cylinder and while the exhaust port remains open,

and in introducing a relatively small supplementary charge under a pressure higher than atmospheric pressure towards the end of the atmospheric admission period.

7. A method of charging two stroke cycle internal combustion engines which comprises introducing the main charge by atmospheric pressure,

by controlling an inlet orifice so that the said inlet orifice is opened when the exhaust gases are moving outwardly through the exhaust passage as a consequence of their mass exit from the cylinder and while the exhaust port remains open, and in introducing supplementary charge under a pressure higher than atmospheric pressure and separately from the said main charge towards the end of the atmospheric admission period."

8. A two stroke cycle internal combustion engine wherein the burnt gases are discharged from the cylinder through a main outlet substantially as a mass and fresh charge is admitted by atmospheric pressure through a main inlet which is opened, while the main outlet is still open,

when the burnt gases are moving outward through the exhaust passage as a consequence of their mass exit from the cylinder and cause a suc ion effect to beexerted in the cylinder, the said engine having a supplementary inlet in connection through a 'duct with a compressor, and means for controlling said supplementary inlet for the introduction of supplementarycompressed charge during the main atmospheric charging period.

9. A two stroke cycle internal combustion en?- gine wherein the burnt gases are discharged from the cylinder through a main outlet substantially as a mass and fresh charge is admitted by atmospheric pressure through a main inlet which is opened while the main outlet is still open, when the burnt gases are moving outward through the exhaust passage as a consequence of their mass exit from the cylinder and cause a suction effect 10. A two stroke cycle internal combustion en-' gine wherein the burnt gases are discharged from the cylinder through a main outlet substantially as a mass and fresh charge is admitted by atmospheric pressure through a main inlet which is opened while the main outlet. is still open, when the burnt gases are moving outward through the exhaust passage as a consequence of their mass exit from the cylinder and cause a suction effect to be exerted in the cylinder, the said engine having a supplementary inlet in connection through a duct with a compressor, and means for controlling said supplementary-inlet for the introduction of supplementary compressed charge toward the commencement of the main atmospheric charging-period.

11. A two stroke cycle internal combustion engine wherein the burnt gases are discharged from the cylinder through a main outlet substantially as a mass and fresh charge is admitted by atmospheric pressure through a main inlet which is opened, while the main outlet is still open, when the burnt gases are moving outward through the exhaust passage as a consequence of their. mass exit from the cylinder and cause a suction effect to be exerted in the cylinder, and is closed before the main outlet closes, the said engine having a supplementary inlet in connection through a duct with a compressor, and means for controlling said supplementary inlet to commence the introduction of supplementary compressed charge towards the end of the main atmospheric charging period and to terminate said supplementary charge after the closure of the main outlet.

12. 'A two stroke cycle internal combustion engine wherein the burnt gases are discharged from the cylinder through a main outlet substantially as a mass and fresh charge is admitted by atmospheric pressure through a main, inlet which is opened, while the main outlet is still open, when the burnt gases are moving outward through the exhaust passage as a consequence of their mass exit from the cylinder and cause asuction efiect to be exerted in the cylinder, and is closed after the main outlet closes, the said engine having a supplementary inlet in connection through a duct with a compressor, and means for controlling said supplementary inlet to commence the introduction of supplementary compressed charge towards the end of the main atmospheric charging period and to terminate said supplementary exhaust passage as a consequence of their mass exit from the cylinder and cause a suction efl'ect to be exerted in the cylinder, and is closed after the main outlet closes, the said engine having a supplementary inlet in connection through a duct with a compressor, and means for controlling said supplementary inlet to commence the introduction of supplementary compressed charge before the closure 01' the main outlet and to terminate 7 said supplementary charge after the closure of the main inlet.

14. A two stroke cycle internal combustion engine wherein the burnt gases are discharged from the cylinder through a main outlet substantially as a mass and fresh charge is admitted by atmospheric pressure through a main inlet which is supplementary outlet on the cylinder and means to open said outlet at or about the closure 01 the main outlet and to close said supplementary outlet at or about the closure of the last main orifice to close.

MICHEL KADENACY. 

